Currently, a thin film transistor has been widely used in a liquid crystal display technology, an organic electroluminescent display technology and integrated circuits, for example, as a switch of a pixel unit in an active matrix display device or as a basic unit driven by a row of an array substrate, so as to form a gate drive circuit. The display device manufactured by the thin film transistor has the advantages of simpler technical process and higher integration of the panel. Therefore, the thin film transistor plays an important role in the flat panel display technology.
After a long term research and development, the inventor of the disclosure found that the thin film transistor generally uses a transparent glass as a substrate, silicon nitride or silicon oxide as a gate insulating layer, and an active layer is arranged on a substrate or a gate insulating layer. Because the thermal conductivity glass, silicon nitride and silicon oxide is low, when the current flowing through the active layer is high, the heat generated may not be quickly transmitted to the surrounding environment through the substrate and the gate insulating layer, easy to cause self-heating effect of the thin film transistor, so operating parameters of the thin film transistor, such as the threshold voltage, the ON state current (Ion), the OFF state current (Ioff) and the sub-threshold swing, are changed, thereby affecting the normal operation state of the thin film transistor.